From: Andrew Bartlett <abartlet@samba.org>
Date: Mon, 8 Jan 2018 04:29:19 +0000 (+1300)
Subject: talloc: Remove talloc_abort_magic()
X-Git-Tag: talloc-2.1.11~3
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=00ee9da50b289a68621f2af755d4283fe6cb3bc7;p=thirdparty%2Fsamba.git

talloc: Remove talloc_abort_magic()

The check required for talloc_abort_magic() prevents the 'access after free error'
from being printed.

It is also no longer possible to determine the difference between invalid memory
and a talloc version mismatch as the magic is now random on many platforms.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13210

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
---

diff --git a/lib/talloc/talloc.c b/lib/talloc/talloc.c
index 7721fa4a9c6..3569ba75929 100644
--- a/lib/talloc/talloc.c
+++ b/lib/talloc/talloc.c
@@ -429,11 +429,6 @@ static void talloc_abort(const char *reason)
 	talloc_abort_fn(reason);
 }
 
-static void talloc_abort_magic(unsigned magic)
-{
-	talloc_abort("Bad talloc magic value - wrong talloc version used/mixed");
-}
-
 static void talloc_abort_access_after_free(void)
 {
 	talloc_abort("Bad talloc magic value - access after free");
@@ -450,19 +445,14 @@ static inline struct talloc_chunk *talloc_chunk_from_ptr(const void *ptr)
 	const char *pp = (const char *)ptr;
 	struct talloc_chunk *tc = discard_const_p(struct talloc_chunk, pp - TC_HDR_SIZE);
 	if (unlikely((tc->flags & (TALLOC_FLAG_FREE | ~TALLOC_FLAG_MASK)) != talloc_magic)) {
-		if ((tc->flags & (~TALLOC_FLAG_MASK)) == talloc_magic) {
-			talloc_abort_magic(tc->flags & (~TALLOC_FLAG_MASK));
-			return NULL;
-		}
-
-		if (tc->flags & TALLOC_FLAG_FREE) {
-			talloc_log("talloc: access after free error - first free may be at %s\n", tc->name);
-			talloc_abort_access_after_free();
-			return NULL;
-		} else {
+		if ((tc->flags & (~TALLOC_FLAG_MASK)) != talloc_magic) {
 			talloc_abort_unknown_value();
 			return NULL;
 		}
+
+		talloc_log("talloc: access after free error - first free may be at %s\n", tc->name);
+		talloc_abort_access_after_free();
+		return NULL;
 	}
 	return tc;
 }